<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <link rel="stylesheet" href="../static/css/index.css">
</head>
<body>

<div class="password-btn">
    <span></span>
    <input type="text" placeholder="content 属性和 :before 伪类实现带图标的输入框" />
</div>
</body>
</html>